First, it isn't a requirement for me to give you any warning prior to a grief ban. If you are given a warning it's only out of kindness. When you join this server there are many warnings in place that let you know griefing isn't tolerated. Disregarding these rules out of habit, or simple ignorance of these rules, is not a valid defense in a ban appeal.
Now to the crime itself. You advertised in the trade channel that you were selling horses. Myself, missing a couple different styles from my collection, teleported to you in order to see what you were selling. Instead I found you removing a horse from a structure. I immediately vanished and quietly observed your actions while checking the owner of the building in case it did belong to you. During that time you took a white horse on a leash, broke several blocks to widen the opening you had already griefed, and began to walk away from the building. At no point in time did you ever turn back to return the horse. In fact, you continued to advertise that you were selling horses. It was at that time the server went down.
When the server came back online
I quickly leashed the horse and returned it to where it belonged, then waited for you. When you logged back in you wandered around looking for the missing horse before turning back toward the griefed structure. It's my belief that you were more than likely returning to take another horse, not fix the building, but that is just my opinion so it's not a consideration of this ban. I stood in the griefed opening and as you approached I appeared, to halt your entry. I asked you if you had permission to access the building, you said you didn't. It was at that time I banned you. You had plenty of opportunities to back out of your activities on your own, prior to me stopping you. I watched you for at least 10 minutes, in which time you could have put everything back and I would have simply given you a warning. Because you were advertising the SELLING of horses I can easily say you had absolutely no intent on returning anything to it's proper owner, except the blocks on the building so they wouldn't notice you broke in. Put plainly, you were stealing someone else's property and trying everything possible to get away with it.
Normally for griefing 4 blocks (counting a door as 2), I wouldn't have dropped such a heavy ban on you. That said, the severity of your crime is increased by the theft of the horse and the fact you were trying to sell them in the trade channel. Due to your post above I'm not convinced that you are sorry for what you've done. In fact I'm afraid you'll just do it again if I unban you. If you would care to properly apologize for your actions, instead of trying to insinuate that you shouldn't have been banned, I might consider lowering your ban to 7 days.
As further evidence I present a screenshot log of my repair to the structure, and the horse that was stolen (white) is clearly visible back inside;
